The Level I Obstetrical Sonogram Lori Strachowski, MD Clinical Professor of Radiology University of California, San Francisco Chief of Ultrasound, Zuckerberg San Francisco General An Update on AIUM/ACR/ACOG/SRU Guidelines No disclosures. Lecture Goals • Nomenclature, history of “Levels” • 2013 Practice Guidelines – General issues: • Practitioner training, equipment specifications, documentation, fetal safety, etc. – Trimester specific components Highlight updates Helpful tips and references • Standard • Routine •2 nd or 3 rd tri exam • “Screening” Level I
45
Embed
The Level I Obstetrical Sonogram - UCSF CME Level I Obstetrical Sonogram Lori Strachowski, MD Clinical Professor of Radiology University of California, San Francisco Chief of Ultrasound,
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
The Level I Obstetrical Sonogram
Lori Strachowski, MDClinical Professor of Radiology
University of California, San FranciscoChief of Ultrasound, Zuckerberg San Francisco General
An Update on AIUM/ACR/ACOG/SRU Guidelines No disclosures.
Lecture Goals
• Nomenclature, history of “Levels”• 2013 Practice Guidelines
– General issues: • Practitioner training, equipment
specifications, documentation, fetal safety, etc.
– Trimester specific components
Highlight updatesHelpful tips and
references
• Standard• Routine• 2nd or 3rd tri exam• “Screening”
Level I
Level I
• Standard• Routine• 2nd or 3rd tri exam• “Screening”
• Detailed• Targeted• Directed• “High-risk”
Level II Level I
• Standard• Routine• 2nd or 3rd tri exam• “Screening”
• Detailed• Targeted• Directed• “High-risk”
Level II
www.aium.org
OB US Levels
The “level” of exam is predicated by the INTENT of the examination.
History of “Levels”
• MS-AFP screening program• Level I US: to detect obstetric problems
– Incorrect dates– Multiple gestations– Demise
• Level II US: to detect fetal anomalies– Open NTD– Abdominal wall defects
History: OB US Practice Guidelines
ACR and AIUM1986 (rev. ‘90, ‘93, ’96)
ACOG1988 (rev. ’93)
ACR, AIUM, ACOG2003 (rev. 2007)
ACR, AIUM, ACOG, SRU2013
SRU
“AIUM” Guidelines
• www. aium.org– Practice Guidelines
• Obstetric
• Goal: – Provide a minimum
standard for all practitioners of obstetrical ultrasound
2013 additions and modifications in bluewww.aium.org
• 1st Trimester • Standard 2nd or 3rd Trimester• Limited • Specialized
Limited Examination
• Appropriate only when a complete exam is on record• Specific question requires investigation
– Cardiac activity in a bleeding pt– Presentation in a laboring pt– Re-evaluation of fetal size or interval growth – Re-evaluate abnormalities previously noted
Specialized Examinations
• A detailed anatomic examination when an anomaly is suspected based upon:– History– Biochemical abnormalities– Results of a standard or limited exam
1st Trimester US Examination( up to 13 weeks 6 days)
1st Trimester: Indications
• 12 indications, including:– Confirm IUP– Dating– Suspected ectopic– Vaginal bleeding– Assess for certain fetal anomalies, such as
anencephaly, in high-risk patients – Nuchal translucency (NT) measurement when part of a
screening program for aneuploidy …..and others*
*see reference chart in syllabus
1st Trimester: Technique
• Overall Comment– Scanning in the first trimester may be performed either
transbdominally or transvaginally. If transabdominalexamination is not definitive, a transvaginal scan or transperineal scan should be performed whenever possible.
1st Trimester: Technique
• Overall Comment– Scanning in the first trimester may be performed either
transbdominally or transvaginally. If transabdominalexamination is not definitive, a transvaginal scan or transperineal scan should be performed whenever possible.
1st Trimester: Components
1. Gestational sac (presence/location), yolk sac, embryo and measurements
• Uterus (cervix) and adnexa evaluated for a gestational sac, and location if identified
• Comments:– Definitive dx requires a
yolk sac or embryo• Yolk sac
– Thin ring– < 6 mm
1. GS, YS, Embryo, Measurements
• Comments: – Even w/o YS or embryo, any round/oval fluid
collection is highly likely to represent an IUP (absent findings of an ectopic)
• Intradecidual sign may be helpful• CAUTION: Pseudo-gestational sac of EP
– In “pregnancies of undetermined location”, recommend f/u US, +/- serum β-hCG “to avoid inappropriate intervention in a potentially viable early pregnancy.”
1. GS, YS, Embryo, Measurements
• Measurements:– MSD (no embryo)
L+W+H3
1. GS, YS, Embryo, Measurements
• Measurements:– CRL (with embryo)– MSD (no embryo)
• Clinical dates = how old the pregnancy is– AKA: Menstrual ↔ clinical ↔ LMP age– Based on LNMP (assumes a 28 day cycle)– Equal to conceptual (fetal) age + 14 days
• US dates = size = how big the pregnancy is – AKA: US age– Based on US measurements (MSD, CRL, biometry)– Standardized to equate with menstrual age
ACOG/AIUM/SMFM Committee Opinion No. 611
Method for Establishing Due Date, October 2014, acog.org
2. Heartbeat
• Presence or absence of cardiac activity:– Documented by 2-
dimensional video clip ORM-mode imaging
– Use of spectral Doppler imaging is discouraged
NOTE: “+ FHM”, “+ HM” no longer good enough
2. Heartbeat
• Comment:– Present:
• CRL ≥ 2 mm, typically
2. Heartbeat
• Comment:– Present:
• CRL ≥ 2 mm, typically
2. Heartbeat
• Comment:– Present:
• CRL ≥ 2 mm, typically– Absent:
• CRL ≥ 7 mm = demise
2. Heartbeat
• Comment:– Present:
• CRL ≥ 2 mm, typically– Absent:
• CRL ≥ 7 mm = demise• CRL < 7 mm, consider
f/u in 1 week
TIP: Normal embryo grows˜ 1 mm/day
2. Heartbeat
• Measured only if subjectively slow • M mode = safest
TIPS:- 100 –190: avg at 5-9 wks- < 85: poor outcome- < 70: 100% loss rate
3. Number
• Embryonic/Fetal #
• If multiples:– Chorionicity– Amnionicity
What is the chorionicity and amnionicity of this 1st trimester pregnancy?
A. Dichorionic/DiamnioticB. Dichorionic/MonoamnioticC. Monochorionic/DiamnioticD. Mochorionic/Monoamniotic
D i ch o r
i o ni c / D
i a mn i o
t i c
D i ch o r
i o ni c / M
o n oa m
n i ot i c
M on o c
h o ri o n
i c / Di a m
n i ot i c
M oc h o
r i o ni c / M
o n oa m
n i . ..
85%
1%6%8%
What is the chorionicity and amnionicity of this 1st trimester pregnancy?
A. Dichorionic/DiamnioticB. Dichorionic/MonoamnioticC. Monochorionic/DiamnioticD. Mochorionic/Monoamniotic
Mo/Di
Chorionicity and AmnionictyDi/Di Mo/Di
Chorionicity and AmnionictyDi/Di
Caution: Subchorionichemorrhage
When no membrane yet seen,# yolk sacs typically = # amnions
Mo/Di
Chorionicity and AmnionictyDi/Di
Caution: Subchorionichemorrhage
When no membrane yet seen,# yolk sacs typically = # amnions
4. Anatomy
• Embryonic/fetal anatomy appropriate for the 1st
trimester should be assessed.
4. Anatomy
• Embryonic/fetal anatomy appropriate for the 1st
trimester should be assessed.
Rhombencephalon
4. Anatomy
• Embryonic/fetal anatomy appropriate for the 1st
trimester should be assessed.
Probable pysiologic gut herniationTIP: Recommend f/u at 13 wks
4. Anatomy
• Embryonic/fetal anatomy appropriate for the 1st
trimester should be assessed.
Gastroschisis
4. Anatomy
• Embryonic/fetal anatomy appropriate for the 1st
trimester should be assessed.
Anencephaly
5. Nuchal Region
• Nuchal region should be imaged, and abnormalities such as cystic hygroma should be documented.
• If risk of fetal aneuploidy is desired, a very specific measurement, at a specific age (per lab) in conjunction with serum biochemistry is necessary as follows:
NT Measurement Technique
• Mid-sagittal plane• Head, neck, upper thorax,
neutral position
www.aium.org
NT Measurement Technique
• Mid-sagittal plane• Head, neck, upper thorax,
neutral position• Identify amnion
Amnionwww.aium.org
NT Measurement Technique
• Mid-sagittal plane• Head, neck, upper thorax,
neutral position• Identify amnion• Electronic calipers• Perpendicular to long axis• Inner borders of widest space
2nd and 3rd Trimester US Examination(14 weeks, 0 days and above)
2nd & 3rd Trimester Indications
• 28 indications, including:– Estimation of gestational age– Evaluation of fetal growth– Vaginal bleeding– Pelvic pain– To assess for findings that may increase risk for
• Measurement: – Ellipse at skin line– Includes soft tissues of
abdomen
St
SpPV
UV
StomachGB
Persistent Right Umbilical Vein (PRUV)
Recommend fetal echocardiogram
Femural Diaphysis Length (FL)
• Level: – Long axis of femoral
shaft– Most accurate when
beam of insonation is perpendicular to shaft
• Measurement: – Length of ossified shaft– Excludes epiphyses
++
Femural Diaphysis Length (FL)
• Level: – Long axis of femoral
shaft– Most accurate when
beam of insonation is perpendicular to shaft
• Measurement: – Length of ossified shaft– Excludes epiphyses
+
TIPS: - Avoid distal femoral point
++
+
Femural Diaphysis Length (FL)
• Level: – Long axis of femoral
shaft– Most accurate when
beam of insonation is perpendicular to shaft
• Measurement: – Length of ossified shaft– Excludes epiphyses
+
TIPS: - Avoid distal femoral point- If abnormal, use a linear
transducer and measure both
++
+
4. Assessment of Mean Gestational Age
Comment:• “..pregnancy should not be re-dated after an accurate
earlier scan has been performed...”• Discrepancies with menstrual age may suggest a growth
abnormality (i.e. IUGR, macrosomia)• Variability increases with advancing pregnancy
5. Fetal Weight Estimation
• From biometry, with AC most heavily weighted• If prior studies available, must assess interval growth • To assess ongoing growth, suggest 2 - 4 wk interval• Known variability of +/- 15% to actual BW
TIPS on assessing interval growth:- Compare US EDC to US EDC- Use earliest available exam, not the most recent
6. Maternal Anatomy
• Adnexa– Ovaries
• “…frequently not possible to image…”
6. Maternal Anatomy
• Adnexa– Ovaries
• “…frequently not possible to image…”
• Uterus– Myomas:
• Largest• Any potentially clinically
significant
• Adnexa– Ovaries
• “…frequently not possible to image…”
• Uterus– Myomas:
• Largest• Any potentially clinically
significant • Cervix
– Length• Transperineal or EV if
needed Normal cervix: 2.8 - 5.0 cm
UB Vagina
6. Maternal Anatomy Trust Your Vaginal Ultrasound
U
YT
V
Trust Your Vaginal Ultrasound
U
YT
V
Measure residual closed cervix!
7. Fetal Anatomy
• Fetal anatomy:– May adequately be assessed after 18 wks GA – Limitations of the exam should be documented:
Comment: “In multiple gestations and when medically indicated”
Fetal Anatomy: Sex
• Genitalia
Comment: “In multiplegestations and when medically indicated”
• Genitalia
Comment: “In multiplegestations and when medically indicated”
TIPS: - If saving an image, make sure it looks normal
Fetal Anatomy: Sex
• Genitalia
Comment: “In multiplegestations and when medically indicated”
TIPS: - If saving an image, make sure it looks normal- Always respect parents desire to know
Fetal Anatomy: Sex
Overall Comment:
“ While it is not possible to detect all structural congenital anomalies with diagnostic ultrasound, adherence to the following guidelines will maximize the possibility of detecting many fetal abnormalities.”
Overall Comment:
“ While it is not possible to detect all structural congenital anomalies with diagnostic ultrasound, adherence to the following guidelines will maximize the possibility of detecting many fetal abnormalities.”
Hard to miss.
Overall Comment:
“…a more detailed anatomic examination of the fetus may be necessary in some cases, such as when an abnormality is found or suspected on the standard examination or in pregnancies at high risk for fetal anomalies.”
“Level 2” or “Detailed” sonogram
CPT Codes: Level I vs. Level II
• 76805– Ultrasound, pregnant uterus, real time with image
documentation, fetal and maternal evaluation, after first trimester (> or = 14 weeks 0 days), transabdominal approach; single or first gestation.
• 76811– Ultrasound, pregnant uterus, real time with image
documentation, fetal and maternal evaluation plus detailed fetal anatomic examination, transabdominal approach; single or first gestation.
CPT Codes: Level I vs. Level II
• 76805– Ultrasound, pregnant uterus, real time with image
documentation, fetal and maternal evaluation, after first trimester (> or = 14 weeks 0 days), transabdominal approach; single or first gestation.
• 76811– Ultrasound, pregnant uterus, real time with image
documentation, fetal and maternal evaluation plus detailed fetal anatomic examination, transabdominal approach; single or first gestation.
Level I vs. Level II “Is everything OK?”
• Level I– Specificity: 99%– Sensitivity:
• RADIUS study, 19931: 35%• Helsinki US Trial, 1990 2: 52%
• Level II– Sensitivity: > 90%
1 Ewigman, et.al., N Engl J Med 1993; 329:821-8272 Saari-Kemppainen, et.al., Lancet 1990;336:387-391
More current datais unknown!
TIP: Consider heart, vents and kidneys on all follow-up growth studies
In Summary
• A Level I US is a lot more than looking at the fetus• Adherence to guidelines essentially constitutes a
“standard of care”– Increasing sensitivity– Possibly limiting medico-legal exposure
• Recommend:– Be picky!!!!!– Assume every pregnancy has an abnormality until